Fixed Updated IteratorTestCase

Wrong docblock typehint.
Updated Dual(Recursive)DirectoryIterator

Additions:

- Composite decorating with a SplFileInfo derived class for
  component::current() and leafs
- Added DualDirectoryIteratorTest

Fixes:

- Check on uninitialized (un-rewound) state
- Error in creation of inner-iterators
- Switched to binary case sensitive comparison
- Get/Set flags discrepancy
- Always prefer the first on equality
- Docblocks